Connecting anchors for multiple layer concrete panels



Feb. 10, 1970 M. KORNER 3,494,083

CONNECTING ANCHORS FOR MULTIPLE LAYER CONCRETE PANELS Filed Feb. 6, 19683 Sheets-Sheet 1 Feb. 10, 1970 M. KGRNER 3,494,088

CONNECTING ANCHORS FOR MULTIPLE LAYER CONCRETE PANELS Filed Feb. 6, 19683 Sheets-Sheet 3 United States Patent 3,494,088 CONNECTING ANCHORS FORMULTIPLE LAYER CONCRETE PANELS Manfred Kiirner, Karlsruhe-Durlach,Germany,

assignor to Thor Waerner Filed Feb. 6, 1968, Ser. No. 703,414 Claimspriority, applicatigrli Ge6rmany, Feb. 14, 1967,

Int. Cl. E04c 5/03, 2/06 US. Cl. 52410 3 Claims ABSTRACT OF THEDISCLOSURE A wave-shaped connecting anchor positioned between twoconcrete members and an insulating plate, the anchor being in the formof a closed wire loop having crests and peaks which are in the concreteand extend through the insulating plate.

There are already known prefabricated concrete parts as multiple layerpanels which are also called sandwich panels and which are mainlydestined for exterior walls of buildings. They comprise, for instance, abearing reinforced concrete panel having an approximate strength of to12 cm. the so-called interior layer or interior panel, a face panel ofabout half the strength, also consisting of reinforced concrete, whichas exterior layer or exterior panel is destined for the outside of thebuilding, and an approximately 3 to 4 em. strong intermediate layer ofinsulating material such as Styropor or similar. Since the insulatinglayer will not be able to take up the forces occurring, the exteriorpanel and the interior panel which are usually reinforced by woven steelfabric, are connected to each other by means of one or several steelanchors. The same will not only have to support the dead weight of theexterior Panel at the bearing interior panel during transportation andin the final building, but they will also have to receive the stressesresulting from differences in temperature between said two side panelswhich, in extreme cases, may amount to as much as 50 C.

Corresponding technical literature recommends the center or the centerof gravity of the panels respectively as the most favorable location forthe positioning of the connecting anchors. However, multipie layerpanels are known providing for several anchors beyond the center, foranchors in every corner of the panels, or for anchors distributed allover the panel surface. The anchors already known are of double T shape,L shape or in the form of an angle with adjacent clamping legs to beclamped into the woven steel fabric of one of the two concrete panels.There are also known less heavy anchors in the form of hairpins orneedles, provided with toothed edges. Since the insulating layer doesnot offer any protection againstcorrosion, the connecting anchors willhave to be made from corrosion and acid resistant material such asspecial steel. Furthermore, light weight connection nails of syntheticmaterial are also known.

The present invention provides for anchors to connect multiple layerreinforced concrete panels of the type described above and for multiplelayer panels equipped with said anchors, in which the forces occurringwill be received in a particularly favorable manner, while theirassembly will be as simple as possible.

The connecting anchor according to the present invention ischaracterized in that it comprises a wavy or jagged ring bent from wirein the form of a crown, which, preferably, has four wave crests or jagseach towards each of the two sides. But the ring may also have any othernumber of jags, for instance, 3, 6, or 8. Due to the bridges of thiscrown-like ring directed towards all sides,

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stresses acting into all directions especially in the case of thermalexpansion will be received in an ideal manner. In particular, saidmulti-jagged ring will receive directly horizontally and verticallyacting forces. Apart from final installation of the composite panel,this will also be important with a view to transportation, since duringshipment the panels may be placed without any risk both on their shortor on their long edges.

According to another feature of the present invention the total heightof the waves or jags of the ring or crown anchor is greater than thedistance of the reinforcement of the two concrete panels consisting forinstance of woven steel fabric, by such an amount that it will bepossible to insert additional steel, for instance, simple straight steelrods, between the jag tops and panel armouring, said additional steelanchoring the connecting anchors against the armouring of the two panelsand thus even the latter against each other.

According to the present invention an especially simple method toproduce the anchors mentioned above is to start with bending a wire intoa plane polygon, preferably a square, in which the two wire ends areoverlapping on one side of the polygon. Then the corners together withparts, preferably the halves of the adjacent sides are bent out of theoriginal plane by approximately into the same direction. Thus productionis effected by the minimum number of simple steps. In the case of panelsin the form of an oblong rectangle the production of the anchors may bebased upon an oblong rectangle similar to that of the panel shapeinstead of a square.

According to the present invention the anchor ring will be favorablyinserted in the production of composite panels such that the center ofgravity of the panels will be located in the center of the same and theanchor jags in planes partially parallel to one pair of edges, partiallyparallel to the other pair of edges. This will result in especiallyfavorable reception of forces without involving any detrimental moments.It is not important which side of the jagged ring is located in one ofthe panels and which in the other, so that in this respect any errors inthe production of composite panels are not liable to occur. Insertion ofthe anchor between the woven steel fabrics will also be extremelysimple, as any exact mutual position will not have to be observed,because the additionally inserted steel will be able to bridge distancesof any size.

Further details of the present invention may be seen from the followingspecification and claims.

The drawings show a preferred embodiment of the present invention; inthe same FIG. 1 shows a perspective view of a connecting anchor,

FIG. 2 shows a connecting anchor according to FIG. 1 in an intermediateproduction step,

FIG. 3 is a cross section through the center part of a multiple layerpanel according to the present invention,

FIG. 4 is a top view of a multiple layer panel according to the presentinvention.

FIG. 1 shows a connnecting anchor 1 bent from special steel wire in theform of a jagged ring with 4 jags towards each side. The jag tops A, Aand B, B of one side are located in pairs opposite each other and, inaddition, on a circular line. The same applies to the jag tops A A and BB, of the other side.

In the production, as shown in FIG. 2, first a square is bent from thewire, the wire ends 2 and 3 overlapping each other side by side for acertain length. They may be lying loosely side by side or they may beconnected to each other by welding, winding or similar. It will even bepossible to butt-joint the wire ends and to weld the same in thisposition. Accordingly, the square may also be composed of several wirepieces.

After the square has been made, the corners A, A, B, B together with theadjacent lateral parts 4 and 5 and the bisecting points A A' B B' of thesquare sides are bent out of the plane of the original square into onedirection by 90 so that they will occupy the position identified by aline of dots and dashes. All bending points are subject to angles of 90.This is the final shape of the connecting anchor. But it will also bepossible to extend or to compress the jagged ring to increase or reducethe angles. However, in each case, the total height h of the jags willhave to be greater than the distance of the concrete panel armouringwhich the anchor is to connect, by such an amount as to enable bracingby means of the additional steel 9.

As already mentioned, the crown-like jagged or wavy ring of "theconnecting anchor may also have more or less than 4 jagged Waves.

Production of the multiple layer panel according to FIGS. 3 and 4preferably starts with planely covering a shuttering panel =6 which hasbeen smoothly polished, grooved or similar according to the desiredsurface form of the exterior wall. The woven steel fabric 7 of theexterior reinforced concrete panel 8 is placed upon the shuttering panel6 by means of distance pieces, and the connecting anchor 1 is insertedinto the center of the panel also by means of distance pieces such thatthe jag tops A and B are projecting through the woven steel fabric 7.Connection between the anchor 1 and the woven steel fabric 7 is effectedby additional steel 9 arranged parallel and/ or crosswise. Now, thefirst layer-usually the exterior or face panel-is concreted, Naturally,the interior panel may also be concreted first and on the bottom.

Thus the insulating layer 12 shall be positioned, the jags of theconnecting anchor 1 being points projecting through said layer. This mayfavorably be effected without any detrimental deformations with, forinstance, plastic foam panels which are usually 3 to 4 cm. strongmeasuring 100 x 50 cm.

Subsequently the woven steel fabric armouring 10 of the second concretepaneL-in the embodiment according to IFIG. 3 the bearing interiorconcrete panel 11-is again provided with distance pieces in which case,regarding its connection 'with the connecting anchor .1 by means ofadditional steel 9 arranged parallel and/ or crosswise, the same will beapplicable as for the face panel 8. After concreting upon said layer 11the result will be a prefabricated three layer element of maximumstability and at the same time of free mutual mobility of the twoconcrete panels 8 and 11 around the center of gravity as a fixed point.

As may be seen from FIG. 4, the struts 4 and 5 of the connecting anchor1 which are at right angles towards each other and which are located inplanes parallel to the panel edges, will receive both the vertical andthe horizontal forces of pressure and tension.

In addition and if so desired, both panels of the prefabricatedstructural element may be connected by nails provided with teeth orsimilar 13 of a type already known and made from special steel or anyother corrosion resistant material 'within the area of the centeranchor, but also in any other location such as in the corners.

The construction may also be modified otherwise without extending beyondthe scope of the present invention. In particular, the anchor ring mayconsist of several independent parts to be assembled when making thecomposite panel such that the same technical effect will be obtained bythem jointly as in the present embodiment. Several angular anchors ofthe type above may also be arranged in a circle around the center ofgravity of the panels.

What I claim is:

1. A connecting device for a plurality of concrete members including aninsulating plate between said concrete members comprising:

(a) an anchor alternately intersecting said insulating plate,

(b) said anchor being positioned in said concrete members on each sideof said insulating plate,

(c) said anchor being in the form of a closed wire loop forming anopening having an axis substantially perpendicular to said concretemembers,

(d) said anchor including plural pairs of spaced parallel arcuatesegments of wire, one pair being disposed in substantially right angularrelationship to a second pair of arcuate segments the contiguous ends ofthe segments being interconnected and forming peaks pointing in onedirection and positioned in one of said members, each pair of segmentsalso forming crests pointing in the other direction and positioned inthe other of said members.

2. A connecting device as defined in claim 1 including reinforcing rodsin said members.

3. A connecting device as defined in claim 1 wherein the points of saidcrests are coplanar and the points of said peaks are coplanar, saidplanes being parallel to said plate.

References Cited UNITED STATES PATENTS 3,237,357 3/1966 Hutchings 52--4l0 3,338,017 8/1967 Ernst 52685 FOREIGN PATENTS 14,328 2/ 1926Netherlands. 299,433 7/ 1917 Germany. 128,390 6/1919 Great Britain.

HENRY C. SUTH-ERLAND, Primary Examiner U.S. Cl. X.R. 52648, 650, 712

